O2 Sensor Simulator

All performance enthusiasts are looking for any possible way to
increase the power and efficiency of their engine. Most have added a cold
air intake with a K&N type air filter to allow maximum airflow into
the engine for starters. The engine itself and the Engine Control Module (ECM)
are then modified in thousands of different ways for horsepower gains.

The modified engine now produces a larger amount of exhaust gases then
the stock exhaust system was designed to handle so it's time for another
upgrade. Aftermarket headers, larger pipes, high flow catalytic
converters and high flow mufflers are all employed to allow these gases to
exit as freely as possible reducing the effort of the engine to expel
them.

All cars and light trucks made since January 1, 1996 have an On Board Diagnostic
system (OBDII) that monitors all of the sensors in the car. When one of
the sensors sends a signal that is not within the manufacturers
specifications the OBDII system logs an error message. Why is this
important? If you have removed your catalytic converter or even installed
a high flow cat you probably already know why: an error from the secondary
oxygen sensor will illuminate the Check Engine Light (CEL) and you will
not be able to pass emissions.

Catalytic converters of often removed because they are the single most
restrictive part of the exhaust system. With the increased flow comes
another increase: pollution. The oxygen sensor will sense the high content
of carbon monoxide and hydrocarbons and signal the OBDII system. This will
illuminate the CEL and can cause the car to run on limp mode actually
reducing performance. To prevent the error caused by the increased
emissions an Oxygen Sensor Simulator can be installed.

The function of the Oxygen Sensor Simulator or O2 Sim is to mimic the
signal of an O2 sensor sensing the proper levels of emissions. The O2 sim
has an output signal wire that will replace the O2 sensor's signal wire to
the engine control module. Now, with the cat removed, the check engine
light will be off and no error message will be logged.

It is advised to use one of these devices for off road use only. They
are NOT street legal. The oxygen sensor simulator may allow you to pass
today's emission inspection because the test merely reads the OBDII log to
see if there are any emission related error codes.